Toughening of a Polymer Network by the Addition of a Small Amount of Large-Sized Multicyclic Chains

Topological interactions between cyclic and linear polymers have attracted significant attention to exploring the properties of soft materials. However, the complete picture of the cyclic–linear topological interactions is unknown. In this study, a blend system composed of a polymer network and a small amount of large-sized (multi)cyclic polymers (cyclic chain-mixed network, CMN) was prepared to achieve a reinforcing effect via rotaxane or catenane formation. CMNs can be toughened by tuning the topological variables of the (multi)cyclic chains (size and number of cyclic units) and the cross-link density of the network. The toughening was maximized when the molecular weights of the cyclic units were comparable to those of the network loops and the number of rings per molecule was approximately 5. This article suggests that CMNs can control the mechanical properties of networks containing cyclic chains using a single component and proposes a topological design for fabricating tough CMN materials.